In normal mode, I started SM and had yahoo.com (homepage) and this forum page open. Memory steadily was increasing and CPU hovering low. Restarted and opened the same tabs - this time no memory ramp and even lower CPU. When I've seen the very erratic CPU usage, I've had 4-8 tabs open, closing some didn't offer much change. It is like something on a page will trigger the unexpected behavior and it will stay that way until close.

Justinh wrote: Is there a change in the JS engine that makes it be 'busier' than previous generations?

Not that I'm aware of. Mind you, I'm also not aware of the constant changes going on to the coding of all the commercial websites out there either. Website coding can change daily, but still look the same.

For example - a search results page on Google just sits there, doesn't refresh yet screams away at the CPU, why? You'd think that it must be because of enhanced functionality or something, yet bizarrely, when you turn off JS on that site, the functionality improves! Hidden search options and filters appear!

For sites that are a permanent pain, like Google and others, I use YesScript, which is a simple one click blacklist that stops JS running on a list of chosen sites. For anything else, I just use a simple JS toggle button, but rarely need it.

Oddly, different people sometimes get different results on the Net. For example, I bet that for some people Google 'works just fine'. Well, good for them, but I just know what sites don't work great for me and block the JS on them or move on.

What catches people out is that they assume that you'd need 20 or 30 sites open for the CPU* to scream away - nope, just 1 'rogue' one will do it.

* high RAM use is pretty tiresome, but it's high CPU use that grinds things to a halt.

Metal Lion latest SeaMonkey & Thunderbird Themes - Sea Monkey and Silver Sea Monkey"The only thing necessary for the triumph of evil, is for good men to do nothing." - Edmund Burke (attrib.)

I installed Noscript and tried it a bit. I think it does help. But what a pain - I have to set options for almost every page, then even then sometimes it is not clear which domain's script has broken the page.